A backplane generally comprises a printed circuit board having a number of card connection slots or bays. Each slot or bay comprises, e.g., one or more modular signal connectors or card edge connectors, mounted on the backplane. A removable circuit board or “card” can be plugged into the connector(s) of each slot. Each removable circuit board contains drivers and receivers necessary for communication of signals across the backplane with corresponding drivers and receivers on other removable circuit boards.
One or more layers of conductive traces are formed on and/or in the backplane. The traces connect to individual signal connection points at the various slots to form data lines and control lines.
In U.S. Pat. No. 6,812,803, entitled “Passive Transmission Line Equalization Using Circuit Board Through-Holes,” issued Nov. 2, 2004, and incorporated herein by reference, an inventor of the present application describes a high-speed router backplane design. This design is applicable to extremely high signaling speeds, large panel sizes, and high overall throughputs. In U.S. patent application Ser. No. 10/454,735, entitled “High-Speed Router with Backplane Using Tuned-Impedance Thru-Holes and Vias,” filed Jun. 3, 2003, and incorporated herein by reference, an inventor of the present application describes related technology for tuned-impedance vias. And in U.S. patent application Ser. No. 11/009,408, entitled “Backplane with Power Plane Having a Digital Ground Structure in Signal Regions,” filed Dec. 8, 2004, and incorporated herein by reference, an inventor of the present application describes related technology for further improvements in such backplane design.